Euphorbia prostrata

Walking through Hastings Old Town on 3 October 2014 I spotted a tiny unfamiliar plant growing in the sandy crack between a garden wall and the paved track used by visitors to Hastings Castle. Closer inspection revealed the unique structure of Euphorbia (Spurge). It keyed out in Stace as Spotted Spurge E. maculata without spots on the leaves. However, photographs on the internet didn’t look quite right – the leaves are a slightly different shape, elliptical oval rather than oblong. Further investigation produced a key to five native Californian Euphorbia species, ‘prostrate sandmats’, on the University of California website. It included E. maculata, but my specimen keyed out clearly as Ground Spurge E. prostrata. A diagnostic difference is the hairs on the capsule. In E. maculata they are appressed over the entire capsule, whereas in E. prostrata there is a fringe of hairs along each suture. But it wasn’t in Stace. I looked on the BSBI website where there was a single record. I contacted the BSBI Euphorbia referee, Timothy Walker, who said ‘unlikely but not impossible, send me as much as you can, preferably a whole plant’. There was only one, so I sent a couple of photographs and a piece about 1” long – and confirmation came back within the week.

Euphorbia prostrata. Photo: Jacqueline Rose

The flowers are between 1 and 1.5mm. The pedicels of immature capsules are curved, and the capsules tucked out of the way, but straighten as the capsules mature, giving the plant a spiky appearance. I tried taking a photograph through the lens of my microscope, and blurred though it is it shows the capsule in the mature position, ready to shed its seeds at a touch, displaying its fringes of hairs. Two plants appeared in 2015 and three in 2016. That in the original site has become woody at the base, suggesting the plant, described as an annual, may be growing as a perennial. Matthew Berry has rechristened it, very appropriately, Fringed Spurge.

Microscopic view of Euphorbia prostrata. Photo: Jacqueline Rose

The single previous record for the UK was from London’s Dockland, where it was found in a plant container during a Wild Flower Society meeting. It was sent to Eric Clement, the Aliens referee, for identification. The following year it appeared in the paving cracks below. I don’t know the end of that story.